EPA/Michael ReynoldsThe newly elected members of the U.S. House of Representatives pose of the steps of the Capitol Building in November. New Jersey could lose a seat in Congress when the new Census data is released Tuesday.

TRENTON — For years, New Jersey residents have been packing up and moving to warmer southern states. One of the state’s congressional seats may soon follow.

The U.S. Census Bureau will release state population figures Tuesday that experts predict could cost New Jersey one of its 13 seats in the House of Representatives, which could trigger one of the most contentious congressional redistricting battles in state history.

"If you judge by the overall level of political polarization and interparty hostility, you would certainly predict that," said Rutgers University political science professor Ross K. Baker, who studies Congress.

While New Jersey’s population is expected to grow in the 2010 Census figures, population booms in southern and western states are expected to outpace that of the Garden State.

The House of Representatives’ membership is set at 435, so even though New Jersey is expected to grow in population, it could still lose a seat to a state that is growing faster.

Having one less seat means one less vote in the House, one less electoral vote in presidential elections, and one less person on committees that help shape legislation. If a member with a lot of political clout loses his seat, it could mean less influence for New Jersey, and the possibility that the state would receive less federal funding.

If New Jersey loses a seat, it would mark the fourth time in state history the congressional delegation has contracted.

New Jersey previously shed congressional representation in 1992, 1982 and 1842. Unlike those redistricting years, however, there is no clear answer as to which of New Jersey’s current representatives would be forced to face each other for re-election in 2012 in the 12-district scenario.

"The Democrats will absolutely come up with a plan that puts two Republicans together, and the Republicans will come up with a plan to put the two Democrats together," said Roger Bodman, a prominent lobbyist who led the Republicans’ congressional redistricting efforts 20 years ago.

When New Jersey lost a seat in the 1990 Census, Democratic Reps. Frank Pallone of Monmouth County and Bernard Dwyer of Middlesex County were thrown in a district together. Dwyer retired, saving the party from a fierce primary fight.

After the 1980 Census cost New Jersey a seat, Republican Rep. Millicent Fenwick of Somerset County was put in the same district as Republican Rep. James Courter of Warren County, but Fenwick chose to leave her House seat to run for U.S. Senate. In 1842, the state stopped electing its delegates at-large and went to a district system, and lost one seat after the majority Whig Party shrank the size of the House from 242 to 223.

The 2012 version of congressional survivor promises to be far less predictable.

As of next month, New Jersey will have seven Democrats and six Republicans in the House. If that number shrinks from 13 to 12, Republicans will likely argue that since they received a majority of votes in this year’s statewide elections, they should have equal representation in the House. Democrats dismiss that argument because they say 2010 was not a typical year in New Jersey, a state that usually leans Democratic.

NEW BOUNDARIES

But right now, the leaders of the political parties are consumed with drawing new state legislative district boundaries, and don’t want to speculate about a process that wouldn’t begin until the latter half of next year.

"I think any time you go from 13 seats to 12, there will be some vested interests at stake," said Republican state chairman Jay Webber, an assemblyman from Morris County. "I look forward to the process in the summer, but all I’m doing now is looking forward to it."

Those appointed to the 13-member commission will be tasked with redrawing the congressional districts, but wouldn’t have carte blanche. Districts must meet a number of standards, including having equal populations and preserving minority voter rights.

"It’s not just the politics," said Bodman. "As a partisan, you start from that. … Then you absolutely have to comply with these rules."

Andrew Mills/The Star-LedgerLeonard Lance, pictured in a 2009 photo, is a likely target for redistricting because of his lack of seniority and sprawling district.

The commission will include six members appointed by Republican leaders, six by Democrats, and a tie-breaking member agreed upon by both sides. If party leaders cannot agree on the 13th member, the state Supreme Court will pick the potential tiebreaker.

More detailed Census figures released next year are expected to show New Jersey’s population shifting farther south in the state, making it unlikely one of the three districts south of Interstate 195 would be eliminated. And two districts dominated by minority groups — the Newark-based 10th District and Hudson County-based 13th District — can’t be tampered with. That leaves seven districts in play — four represented by Democrats and three by Republicans.

Rutgers professor Alan Rosenthal, who was the tie-breaking member on New Jersey’s redistricting commission in 1992, said several factors beyond population shifts may sway the redistricting. Seniority of the incumbents and the importance of their committee assignments have played a role in past redistricting, though the political climate is now different, he said.

The member with the least seniority will be Republican Jon Runyan, who starts his first term in January representing South Jersey’s 3rd Congressional District.

"The nature of politics has changed a lot in the last 20 or 30 years. It’s become much more ideological and much more partisan," Rosenthal said. "So I don’t know whether congressional seniority will mean anything. If I were the tiebreaker, it would mean something to me."

POTENTIAL TARGET

Rep. Leonard Lance, (R-7th Dist.), has the second-least seniority in New Jersey’s delegation and represents a district that sprawls across central New Jersey, including parts of Hunterdon, Union, Somerset and Monmouth counties, making his district a potential target.

But Lance said he expects the Census to show his district growing at a faster rate than some other parts of the state.

"I think it should be based largely on population," Lance said. "There’s been growth throughout the district and southern New Jersey as well. The area of New Jersey that has not grown as rapidly, as I understand it, is northeastern New Jersey."

A report released in September by Election Data Services, a firm that specializes in redistricting, projected New Jersey was likely to join Illinois, Iowa, Louisiana, Massachusetts, Michigan, Missouri and Pennsylvania in losing a House seat.

New York and Ohio would each lose two seats, based on the study. A December 2009 report by Politidata, a political data analysis firm, also points to New Jersey losing a seat.

Those likely to gain seats include Texas with four, Florida with two, and Arizona, Georgia, Nevada, South Carolina, Utah and Washington with one each, according to the Election Data Services report.

Still, New Jersey could be spared, said Election Data Services President Kimball Brace.

"You are kind of on the edge," Brace said. "You might be on the outer edge, but you are still on the edge."

Editor's note: A previous version of this story misstated the counties Rep. Leonard Lance (R-7th Dist.) represents. He represents parts of Hunterdon, Union, Somerset and Monmouth counties.